An electric vehicle is required to incorporate a battery as an electric power supply for an electric motor which rotates a wheel. Patent Literature 1 discloses a charging method in which a charger is connected to a battery all the time during storage of the vehicle because the SOC (state of charge) of the battery is reduced by self-discharge in a state in which the battery is not used and left alone. In the charging method disclosed in Patent Literature 1, the charger is connected to the battery in a state in which the battery is mounted to the vehicle body.